Using organosilicon compounds, University of Wisconsin-Madison Professor Emeritus of chemistry Robert West and his UW-Madison colleagues have developed a new generation of rechargeable lithium ion batteries whose lifetimes are more than twice as long as the batteries now used in the tiny medical devices.

"It turns out the organosilicon compounds are really good for improving lithium battery technology," says West, whose new battery technology powers a microstimulater not much larger than a pencil lead and that can be injected near target nerves to help overcome the faulty nervous system wiring at the heart of Parkinson's, epilepsy and incontinence.

"The idea is that whenever you have a broken nerve connection, you can supply the electrical impulse to complete the circuit," West explains. His group developed the electrolyte, the electricity-conducting liquid that is the heart of the battery: "They're very flexible. They don't solidify. They're stable, non-flammable, non-toxic and they pose no threat to the environment," says West.

In the context of the lithium battery, West's group has been making and testing silicons that are specially formulated to conduct electricity in a very compact environment. In the lithium battery, charge is maintained as lithium ions flow between the battery's positive and negative electrodes. "The battery requires something the ions can go through easily. We had to tweak the organosilicon molecules to get higher conductivity and stability," says West.

A critical advantage of the new battery technology is lifespan: "If you're going to implant these things, you want a lifetime of at least 10 years," says West, whose organosilicon batteries are projected to power the tiny implantable devices for more than twelve years.